Poly photo-responsive

Analogous photoresponsive peptide and polypeptide systems are being developed the photochemical properties of poly[W -p-(phenyl-azo)benzoyl-L-a,/8-diaminopropionic acid] have been examined, and the first example of photoregulation of permeability across a membrane has been achieved by the use of a new polyvinyl/poly-peptide graft copolymer composed of a photoresponsive copolypeptide branch from /3-p-phenylazobenzyl L-asparate and /3-benzyl L-asparate attached to a poly(Bu methacrylate) backbone.Papain activity has similarly been regulated by anchoring a photo-responsive azo group to the enzyme backbone. ... 

Liu XH, Wang XG, Liu DS. 2001. Synthesis and characterization of photo responsive and thermosensitive poly(N isopropylacrylamide co 2 [4 (4 ethoxyphenyl)azophenox... 

Suitable materials for the use in such systems include anthracene, sulfur, and selenium. In addition to anthracene, other organic photoconductive materials most attractive to PVK, have been the focus of interest in electrophotography. Poly(vinylcarbazole)s, when sensitized with TNF exhibit a good photo-response and discharge characteristics and a low dark decay. However, the dark decay depends upon the polarity of the surface charge. 

Photoresponsive membranes were obtained from mixtures of poly-ethersulfone (PES) and azobenzene-functionalized and p-CD-functiona-lized PES, with a PEG spacer between PES and azobenzene or PES and p-CD end moieties (PES-PEG-azo and PES-PEG-p-CD). Membranes of 60-70 pm, prepared from suitably blended mixtures of PES with PES-PEG-azo and PES-PEG-p-CD under visible light, exhibited photo-responsive permeability to water. Upon alternate irradiations with 365/450 nm light the membrane pores were open/closed, due to the exclusion/inclusion of azobenzene from/into the p-CD cavities. ... 

Fig. 13 Structures of photo-responsive poly(vinyl ether)s...

Irk, Af. Stimuli-Responsive Poly(N-isopropylacrylamide), Photo- and Chemical-Induced Phase Transitions. VoL 110, pp. 49-66. 

A flow injection optical fibre biosensor for choline was also developed55. Choline oxidase (ChOX) was immobilized by physical entrapment in a photo-cross-linkable poly(vinyl alcohol) polymer (PVA-SbQ) after adsorption on weak anion-exchanger beads (DEAE-Sepharose). In this way, the sensing layer was directly created at the surface of the working glassy carbon electrode. The optimization of the reaction conditions and of the physicochemical parameters influencing the FIA biosensor response allows the measurement of choline concentration with a detection limit of 10 pmol. The DEAE-based system also exhibited a good operational stability since 160 repeated measurements of 3 nmol of choline could be performed with a variation coefficient of 4.5%. 

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